add small bash script to cloudbuild.yaml

Question

I have a cloudbuild.yaml file for google cloud (GCP). I would like to grab the version from package.json using a simple bash script $(node -p -e "require('./package.json').version") (or any other way). How can I add this to my cloudbuild.yaml file?

I tried putting the script in substitution but it didn't work.

# gcloud submit   --substitutions=_VERSION="1.1.0"

steps:
  # build the container image
  - name: "gcr.io/cloud-builders/docker"
    args: ["build", "-t", "gcr.io/${_PROJECT_ID}/${_IMAGE}:${_VERSION}", "."]
  # push the container image to Container Registry
  - name: "gcr.io/cloud-builders/docker"
    args: ["push", "gcr.io/${_PROJECT_ID}/${_IMAGE}:${_VERSION}"]
  # build the container image
  - name: 'gcr.io/google.com/cloudsdktool/cloud-sdk'
    entrypoint: gcloud
    args:
      [
        "run",
        "deploy",
        "${_SERVICE_NAME}",
        "--project",
        "${_PROJECT_ID}",
        "--image",
        "gcr.io/${_PROJECT_ID}/${_IMAGE}:${_VERSION}",
        "--platform",
        "managed",
        "--allow-unauthenticated",
        "--region",
        "${_REGION}",
        "--set-env-vars",
        "${_ENV_VARS}",
        "--ingress",
        "internal-and-cloud-load-balancing",
        "--quiet",
      ]
images:
  - gcr.io/${_PROJECT_ID}/${_IMAGE}

substitutions:
  _REGION: us-east1
  _PROJECT_ID: my-dev
  _SERVICE_NAME: my-client
  _IMAGE: my-client
  _VERSION: $(node -p -e "require('./package.json').version")
  _ENV_VARS: "APP_ENV=dev"

Answer 1

It's one of the bad side of Cloud Build. You can't pass variable from one step to another one. Only /workspace is kept between steps. And the substitution variables are only static (predefined or set at pipeline runtime).

The solution here isn't so easy.

• You need to add a step to get the version and write it in a file

- name: 'node'
  entrypoint: bash
  args:
    - -c
    - node -p -e "require('./package.json').version" > /workspace/node_version

• Then use it in your steps, like that

- name: "gcr.io/cloud-builders/docker"
  entrypoint: bash
  args: 
    - -c
    - |
       VERSION=$${cat /workspace/node_version}
       docker build -t gcr.io/${_PROJECT_ID}/${_IMAGE}:$${VERSION} .

The double dollar $$ is to indicate that is a linux command and not a Cloud Build variable

Answer 2

Based on Guillaume's answer, you can use a bash script with two $$ instead of 1 $ , like so $$(node -p -e "require('./package.json').version") . However , if the command you're attempting to use isn't available ( node will not be available), it's best to pull it from a file that you can make in the step above like in Guillaume's answer:

- name: "gcr.io/cloud-builders/docker"
    entrypoint: bash
    args: 
      - -c
      - docker build -t gcr.io/${_PROJECT_ID}/${_IMAGE}:$$(cat ./package_version) .